Package: emacs25
Version: 25.2+1-6
Severity: minor
This bug has been reproducible since at least the emacs23 days, and is
available in emacs in both stretch/testing/sid as well
as ubuntu from 9.04 'jaunty' through to 18.04 'bionic'
Heavily recursive emacs lisp functions are hitting some limit, that is not the
limit of how much memory emacs has access to.
To hit this limit you need a simple file that is made by 2 parts.
1) seq 11718 > seqfile
you can then edit seqfile with emacs and copy the contents. you'll need that
for later.
2) some helper functions (F, nullp & map), 2 setqs to set max-lisp-eval-depth
and max-specsdl-size and the function G
File Edit Options Buffers Tools Help
(defun nullp (l)
"is this null?"
(equal '() l))
(defun map (f l)
"map function?"
(if
(nullp l)
'()
(if (listp l)
(if (= 1 (length l))
(list (funcall f (car l)))
(if (> (length l) 1)
(cons (map f (car l))
(map f (cdr l)))))
(funcall f l)
)))
(setq max-lisp-eval-depth (expt 2 17))
(setq max-specpdl-size (expt 2 17))
(defun F (L)
(message ".") )
(defun G (L) (map 'F L))
(G
'(
<insert file seqfile here>
))
then run the above, line by line. if you try to run G
...the result is a crash of emacs in its entirety.
themusicgod1@wicksell:~/emacs$ emacs seqfile0-simple
Fatal error 11: Segmentation fault
Backtrace:
emacs[0x50a5fe]
emacs[0x4f0bf9]
emacs[0x508d4e]
emacs[0x508f08]
emacs[0x508f95]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x110c0)[0x7fcbe20fe0c0]
emacs[0x44515b]
emacs[0x447985]
emacs[0x44e961]
emacs[0x4517ce]
emacs[0x432568]
emacs[0x455ff6]
emacs[0x4562ff]
emacs[0x45646c]
emacs[0x55adee]
emacs[0x565bc9]
emacs[0x5660bd]
emacs[0x563b2b]
emacs[0x565bc9]
emacs[0x566365]
emacs[0x5659d9]
emacs[0x566365]
emacs[0x5659d9]
emacs[0x5660bd]
emacs[0x566263]
emacs[0x5657f8]
emacs[0x5658da]
emacs[0x5659d9]
emacs[0x566365]
emacs[0x5659d9]
emacs[0x5659d9]
emacs[0x566365]
emacs[0x5659d9]
emacs[0x5660bd]
emacs[0x566263]
emacs[0x5657f8]
emacs[0x5658da]
emacs[0x5659d9]
emacs[0x566365]
emacs[0x5659d9]
emacs[0x5659d9]
...
Segmentation fault
I've looked a little bit at the stack trace of what this crash looks like in
the ubuntu bug report.
As you can imagine with a highly recursive program, it's deep.
https://bugs.launchpad.net/ubuntu/+source/emacs23/+bug/508618
one thing that is *not* causing this is the memory of emacs being exhausted,
since monitoring the memory used by the
process in question leads to observing it's using a small % of the system
memory on any machine I've tested.
What should happen is that emacs should give some error message(some suggested
in the ubuntu ticket), and not crash.
Or it should be documented somewhere what this limit is, and why is it in
emacs. Segfaulting at random when you have
hundreds of frames can be quite...jolting :)
-- System Information:
Debian Release: 9.2
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable-debug'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 4.9.0-3-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_CA.UTF-8, LC_CTYPE=en_CA.UTF-8 (charmap=UTF-8),
LANGUAGE=en_CA:en (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages emacs25 depends on:
ii emacs25-bin-common 25.2+1-6
ii libacl1 2.2.52-3+b1
ii libasound2 1.1.3-5
ii libatk1.0-0 2.22.0-1
ii libc6 2.24-11+deb9u1
ii libcairo-gobject2 1.14.8-1
ii libcairo2 1.14.8-1
ii libdbus-1-3 1.10.22-0+deb9u1
ii libfontconfig1 2.12.6-0.1
ii libfreetype6 2.6.3-3.2
ii libgdk-pixbuf2.0-0 2.36.5-2+deb9u1
ii libgif7 5.1.4-0.4
ii libglib2.0-0 2.50.3-2
ii libgnutls30 3.5.8-5+deb9u3
ii libgomp1 6.3.0-18
ii libgpm2 1.20.4-6.2+b1
ii libgtk-3-0 3.22.11-1
ii libice6 2:1.0.9-2
ii libjpeg62-turbo 1:1.5.1-2
ii libm17n-0 1.7.0-3+b1
ii libmagickcore-6.q16-3 8:6.9.7.4+dfsg-11+deb9u3
ii libmagickwand-6.q16-3 8:6.9.7.4+dfsg-11+deb9u3
ii libotf0 0.9.13-3+b1
ii libpango-1.0-0 1.40.5-1
ii libpangocairo-1.0-0 1.40.5-1
ii libpng16-16 1.6.28-1
ii librsvg2-2 2.40.16-1+b1
ii libselinux1 2.6-3+b3
ii libsm6 2:1.2.2-1+b3
ii libtiff5 4.0.8-2+deb9u1
ii libtinfo5 6.0+20161126-1+deb9u1
ii libx11-6 2:1.6.4-3
ii libx11-xcb1 2:1.6.4-3
ii libxcb1 1.12-1
ii libxfixes3 1:5.0.3-1
ii libxft2 2.3.2-1+b2
ii libxinerama1 2:1.1.3-1+b3
ii libxml2 2.9.4+dfsg1-2.2+deb9u1
ii libxpm4 1:3.5.12-1
ii libxrandr2 2:1.5.1-1
ii libxrender1 1:0.9.10-1
ii zlib1g 1:1.2.8.dfsg-5
emacs25 recommends no packages.
Versions of packages emacs25 suggests:
pn emacs25-common-non-dfsg <none>
-- no debconf information
